Comparing acid additions between BIAB and traditional mash/sparge

[frankvw]

I did my first BIAB batch last week. So far I've been using the classic three vessel setup (HLT, mash tun, kettle) with good results, but I decided to give BIAB a try just to see if it's all it's cracked up to be. I brewed a simple blonde ale to start with. So far my experiences seem to confirm what I've read: more trub than with sparging, good yield, and the beer looks to be headed for a slightly higher FG, but all should be fine.

Except for one thing: it looks like i stuffed up my acid addition.

Because my local water has a high pH, I usually add 2ml of phosphoric acid to the strike water for lighter styles. Yes, I know there's more to pH control than just that and there are better ways than simply chucking in acid, but I'll get to that sometime in the near future. In recent years I've mashed about 4kg of grains on average into 11 liters of strike water, and 2ml of phosphoric gives me a light style without the harsh bitter undertones I get when I leave the acid out.

My BIAB batch started with 27 liters of water, which is darn close to 2.5 x 11 so I added 5ml of acid... not realizing that because when I sparge using the traditional 3 vessel method I don't acidify my sparging water, and that the acid now stays in the beer. And sure enough, I drew a sample from the fermenter last night and had a taste, and there is a definite acidity to the beer.

So. The question before the house is this: if 2 ml. of phosphoric acid does the job for me in a traditional mash of 4kg of grain into 11 liters of strike water sparged with unacidified water, how do I calculate the proper acid addition for the BIAB water volumes?

Or is acid addition counter-indicated with BIAB and should acidulated malt be used instead? If the latter, why would the acid from acidulated malt be any different; should the quantity of acidulated malt be adjusted for BIAB, and if so by how much?

Questions, questions...

 

[RM-MN]

I'm sure that guessing the amount of acid might be better than not putting any in but knowing what you need is kind of important. There are some pretty cheap pH meter available that will tell you a lot more about what your mash needs than my guessing.

To get the best conversion and flavor the mash pH needs to be right. Get a pH meter (not pH strips) and check one batch about 15 minutes into the mash. You will need to let the pH stabilize before you sample but at this point in this mash it is a bit late to make additions so write down what you found for reference. You can then make a reasonable addition to the next mash at the start to approach the correct range of pH. You may have to adjust that as the grain bill change as that will change the pH of the mash too.

Better still is to send in a water sample for testing so you know what you have in the water, then adjust the mineral additions to achieve the pH needed.

 

[soccerdad]

I have always struggled to keep a meter maintained and calibrated. Someday I will have one of those 1000 dollar meters that isn't so hard to keep the tip moist and the calibration on target. In the meantime, I have found the water calcs with Brunwater and / or Brewers Friend to be very helpful. But as RM-MN notes above, you need to know what is already in your water -- get it tested or use RO water.

I use acid malt as opposed to liquid, but that's just me. Easy to crush it along with my other grains. In general I use 2 to 6 ounces per batch in lighter colored beers. Depends on batch size and grains used.

 

[frankvw]

I'm sure that guessing the amount of acid might be better than not putting any in but knowing what you need is kind of important.

Absolutely. However, what I'm comparing here is 2ml acid into 11 liters of water followed by unacidified sparge water, vs. 5m of acid into 27 litres of water, all of which ends up in the boil (with the sole exception of the water absorbed by the grains, of course).

Adding the same amount of acid per volume water in both cases will give different results, and what I'm after here is finding out how to deal with that.

 

[Morrey]

I support full volume mashes for BIAB with your ph (and other brewing salts) adjusted from the beginning. You'll need properly adjusted ph to get decent mash efficiency for sure. For the sake of argument, lets assume you'll do the no sparge BIAB method like many do, and simply let the bag drain or squeeze.

Acid malts are hard to deal with (at least for me) since they vary so greatly. I have always stuck with lactic or other acid additions to acidify with.

Knowing your starting point (water analysis) is keenly helpful to do adjustments properly. A brewing water calculation program (like Bru'n Water) will take your beginning water and make suggestions for brewing salts and acid additions to meet your goals. If interested, there are several self-help tutorial programs on YouTube for Bru'n Water and other programs. There are other variables to water adjustments than simply acid additions, and it sounds as if your water may potentially benefit from total adjustments. Water management is a whole new frontier, but rest assured the beer you brew will be rewarding as a result of your efforts.

 

[frankvw]

So the general opinion seems to be that simply adding 2ml to the strike water in a traditional mash is something I can get away with (in my case, seeing as it does improve my lighter beer styles by removing harshly bitter notes) but not in BIAB where I need proper water treatment based on a water report, a calculator, and the correct addition of brewing salts.

If I understand the above correctly. (Do I?)

 

[chickypad]

So the general opinion seems to be that simply adding 2ml to the strike water in a traditional mash is something I can get away with (in my case, seeing as it does improve my lighter beer styles by removing harshly bitter notes) but not in BIAB where I need proper water treatment based on a water report, a calculator, and the correct addition of brewing salts.

I don't think I'd put it like that. I think Morrey's point is that it's probably most important to get the mash pH right, whether you're doing full volume BIAB or traditional mash tun. Either way flying blind isn't the best idea but it sounds like you've gotten lucky without knowing what your starting water really is. Full volume mash may change these parameters as it's a thinner mash so you usually need more acid (it's the full volume that makes the difference here, not really the BIAB part. If you BIAB with sparge it's the same as using a regular tun). I'd be surprised if you were that far off based on what you did, but again getting a water report and plugging into a program would be best.

Edit: I read this wrong initially, I thought you were doing 2 ml each to sparge and mash before. My guess is that you have pretty low alkalinity water based on your results so maybe you overshot. But we don't really know.

 

[Morrey]

So the general opinion seems to be that simply adding 2ml to the strike water in a traditional mash is something I can get away with (in my case, seeing as it does improve my lighter beer styles by removing harshly bitter notes) but not in BIAB where I need proper water treatment based on a water report, a calculator, and the correct addition of brewing salts.

If I understand the above correctly. (Do I?)

I wouldn't say that BIAB is inherently different than 3V (or similar) in that you need a water report for BIAB and don't need a water report for 3V.

In either case, properly ph adjusted mash water will impact mash efficiency. Long story short, acidify your mash volumes to the same ratio whether you adjust 11 liters or 27 liters. And if you add more water as a top off, sparge or whatever, sounds like that same ratio needs to be adjusted properly so your beer is not overly acid tasting.

I see not much difference in BIAB or 3V in this regards.

 

[zgja2]

To sum things up. Get a water report, use that water report and the software of your choice to adjust water for each recipe. There is no one size fits all answer for water chemistry.